Manually and electromagnetically operable latching device



R. D. BOLEY 3,209,102

MANUALLY AND ELEGTROMAGNETICALLY OPERABLE LATCHING DEVICE Sept. 28, 1965 2 Sheets-Sheet 1 Filed Feb. 25, 1963 p 1965 R. D. BOLEY 3,209,102

MANUALLY AND ELECTROMAGNETICALLY OPERABLE LATCHING DEVICE I Filed Feb. 25, 1965 2 Sheets-Sheet 2- INVENTOR.

United States Patent 3,209,102 MANUALLY AND ELECTROMAGNETICALLY OPERABLE LATCHKNG DEVICE Robert D. Boley, Milwaukee, Wis., assignor to Square D Company, Park Ridge, 11]., acorporatiou of Michigan Filed Feb. 25, 196 3, Ser. No. 260,593 8 Claims. (Cl. 200-406) This invention relates generally to electromagnetic devices, and more particularly to an electromagnetically or manually releasable latch attachment adapted to be attached to an electromagnetic relay for latching the movable parts of the relay in the energized position, and to an improved electromagnetic structure particularly suitable for the latch attachment.

An object of the invention is to provide an improved latch attachment for an electromagnetic relay.

Another object is to provide an electromagnetic relay latch attachment which is adjustable relative to the relay to compensate for manufacturing variations.

A further object is to provide an electromagnetic relay latch attachment in which a latching means is self-centering to compensate for misalignment between the latch attachment and the relay.

A still further object is to provide an electromagnetic rela-y latch attachment constructed and arranged in such a manner that accidental operation of a manual release for the latching means is prevented and thereby accidental unlatching of the relay is avoided.

Yet another object is to provide an electromagnetic relay latch attachment which is easily attachable to a relay.

Still another object is to provide an electromagnetic relay latch attachment which is interchangeable with a cover of a relay and performs various functions of the cover when secured to the relay in place of the cover.

A further object of the present invention is to provide a floating bearing for a movable armature in an electromagnetic device to compensate for manufacturing toleranees and to reduce wear of the parts.

These and other objects and advantages will appear when the following specification is considered along with the accompanying drawings, in which:

FIG. 1 is a perspective view of an electromagnetic relay having a latch attachment constructed in accordance with the invention secured thereto;

FIG. 2 is an enlarged sectional view of the latch attachment of FIG. 1 taken substantially along line 22 of FIG. 3 and showing a portion of the movable contact carrier assembly of the relay in latched position;

FIG. 3 is a sectional view .of the latch attachment of FIG. 1 taken substantially along line 3-3 of FIG. 2;

FIG. 4 is a perspective view of the latch rod and formed retaining nut of the latch attachment of FIGS. 1-3; and

FIG. '5 is a view similar to FIG. 2, but showing the latch attachment in an unlatching condition and the movable contact carrier assembly of the relay in a returned position.

In ,FIG. 1 there is shown an electromagnetic device which in the particular embodiment shown operates as a latch attachment when it is secured to an electromagnetic relay 12 of the type disclosed in copending application, Serial No. 206,624, filed on July 2, 1962, and assigned to the assignee of this invention, the latch attachrnent 10 being clamped to the relay 12 by a pair of springbiased formed clamps 14 in place of the cover for the relay.

The latch attachment 10 includes a housing preferably moldedof insulating material and formed of two identical halves 16 secured together by a pair of rivets 17. Withinthe housing "164-116 is an electromagnet assembly 3,209,102 Patented Sept, 28, 1965' ice including a centrally apertured encapsulated coil 18 generally rectangular in outer configuration and having ,opposed terminals 19 and 20 (FIG. 3), a generally cylindrical magnetic core 22 (FIGS. 2 and 5) secured in one end of the aperture of the coil 18, and armature guide 24 in the otherend of the aperture of the coil 18, and a generally cylindrical armature 26 reciprocally mounted in the armature guide 24 and having a shading coil 27 adjacent its inner end portion. The coil 18, core 22, armature guide '24, and armature 26 may be held together in any suitable fashion. In the illustrated example, an outer generally U-shaped strap or magnetic yoke having relatively long leg portions 29 and 30 is provided to embrace the coil 18 on three sides. An inner generally U-shaped strap or magnetic yoke having relatively short leg portions 33 and 34 is provided to embrace the coil 18 on a fourth side, the leg portions 29 and '30 being-secured respectively to the leg portions 33 and '34, as by welding. A bight portion 31 of the outer strap is centrally apertured to receive the core 22, and a bight portion 35 of the inner strap is centrally apertured to receive the armature guide 24 with clearance as shown in FIGS. 2 and 5. I

A sponge rubber member 36 is disposed around the armature guide 24 and between the coil 18 and the bight portion 35 of the inner strap. The member 36 acts to secure the coil 18 tightly in position when the leg portions 33 and 34 are secured to the leg portions 29 and 30. The armature guide 24 includes an inner portion 38 of enlarged diameter, the portion 38 being held against an inner shoulder 18:! on the coil 18 by the bight portion 35 and the member 36. The armature 26 includes an inner portion 40 of enlarged diameter, the portion 40 being reciprocable between the core 22 and the enlarged portion 38 of the armature guide 24. The core 22 is provided with a flange 42 which .is rigidly secured in a recess on the inner side of the bight portion 31 of the outer generally U-shaped strap.

The armature 26 is centrally apertured to receive a hollow, generally cylindrical latch operating member 44 which is secured to the armature for reciprocation therewith as a unit, the armature abutting an exteriorly shouldered portion 46 of the latch operating member, and the latch operating member being spun over at 48 against lhe outer end of the armature thereby securing the armature 26 and latch operating member together.

Adjacent the shouldered portion 46 in the direction away from armature 26, the latch operating member 4.4 is enlarged and radially apertured to provide a mounting for three latching balls 50 centered apart and held in the latch operating member by an inner cam surface in the form of a conical frustum surface 52 provided on the core 22, which is provided with an aperture 22a concentric with the conical frustum surface 52 to reciprocably receive the latch operating member.

A compression spring 54 seated at one end on an inner surface of the housing 1616 bears at the other end against a flange 55 provided on the latch operating member 44 to bias the latch operating member toward latching position with respect to a latch rod 56 described here inafter and also to serve as a returnspring for the armature 26. A sponge rubber shock absorber 58 is adhesively secured to the outer side of the bight portion 31 of the outer strap and is covered with a fiber plate 59 to ,facilitate insertion of the electromagnet assembly in the housing 16-1-6. Each housing half 16 is provided with an inwardly projecting lug 60 which serves as a seat for thebight portion 35 of the inner strap of the electromagnet assembly.

A formed retaining nut 62, generally T-shaped, as best shown in FIG. 4, is threadedly secured to an end .of the latch rod 56 and is adapted to be received in a complementary slot in a movable contact carrier assembly 64 of the relay 12, as best shown in FIGS. 2 and 5. The latch rod is provided with two reduced diameter portions 66 and 67 joined by a pair of base-to-base conical frustum portions 68 and 69, the adjoining bases of which form a ridge 70.

The electromagnetic relay 12 is described in detail in the aforesaid copending application, Serial No. 206,624. When a coil 72 (FIG. 5) of the relay 12 is energized, the movable contact carrier assembly 64 will be moved with respect to the latch attachment against the force of a return spring 74 from the position shown in FIG. 5 to the position shown in FIG. 2, to move a plurality of movable contact fingers 75 with respect to a corresponding plurality of stationary contacts (not shown). The opposite end portions of a seat 76 for the return spring 74 will then bear against the housing 1616 of the latch attachment in the same manner they would bear against a cover for the relay 12 which is replaced by the latch attachment. Similarly, in the case of any movable contact assembly which has been inverted in accordance with the teachings of the aforesaid copending application to change the contacts thereof from a normally open to a normally closed condition, seats 78 for overtravel springs 79 associated with the movable contact fingers 75 will then bear against the housing 1616 of the latch attachment instead of against the cover for the relay 12.

In the assembly of the electromagnetic device 10, the core 22 is first staked or otherwise secured in place in the bight portion 31 of the outer strap, and the shock absorber 58 may then be cemented thereto. The latch operating member 44 is then inserted in one direction in the core 22 with the latching balls 50 adapted to engage the frustoconical inner cam surface 52, and the armature 26 is inserted over the latch operating member 44 from the other direction and moved into engagement with the shouldered portion 46, after which the end portion 48 of the latch operating member is spun over. The coil 18 is then inserted between the leg portions 29 and 30 and moved axially of the armature 26 and core 22 into engagement with the bight portion 31, the inner shoulder 18a facing away therefrom. The armature guide 24 is then inserted over the armature 26 and moved into engagement with the shoulder 18a, and the inner strap with the sponge rubber member 36 cemented thereto is placed in position and welded or otherwise secured to the leg portions 29 and 30 of the outer strap to complete an inner subassembly, the member 36 being compressed to hold the coil 18 tightly against the bight portion 31. The spring 54 is then placed on the latch operating member 44 in engagement with the flange 55 thereof, and the fiber plate 59 is placed over the shock absorber 58, after which the housing halves 16-16 are placed around the subassembly and riveted together. The latch rod 56 having the formed retaining nut 62 secured thereto may then be inserted in the latch operating member 44 from the spun-over end portion 48 thereof. It will be seen that when the parts of the device are thus assembled, the clearance between the armature guide 24 and the bight portion 35 of the inner strap permits the armature 26 to act as a centering means to assure proper alignment of the bore of armature guide 24 and the aperture 22a in core 22, so that the close tolerances of the several parts which heretofore have been required to produce a commercially acceptable device are no longer required.

The energization of the coil 72 operates the movable contact carrier assembly of the relay 12 and also moves the latch rod 56 to a latched position, as shown in FIG.

2, in which it will be maintained upon de-energization of the coil 72 and against the force of the return spring 74 by the action of the latching balls 50 against a latch surface provided by the conical frustum portion 69. It

should be noted that the latch rod 56 will not be released .to unlatched. position by an axially inward force, acci' dental or otherwise, applied thereto. Release of the latch rod may be accomplished by energization of the coil 18 of the latch attachment to move the armature 26 into engagement with the core 22, as shown in FIG. 5, or by manually pulling the latch operating member 44 outwardly, for which purpose the outer end portion thereof is provided With a flange 45. The outward movement of the latch operating member 44 allows the latching balls 50 to move outwardly along the cam surface 52 of the core 22 to release the conical frustum portion 69, and the return spring 74 of the relay then returns the movable contact carrier assembly 64 of the relay and latch rod 56 of the latch attachment. Upon de-energization of the coil 18 or release of the latch operating member 44, the spring 54 will return the latch operating member 44 to the position of FIG. 2 in which the latching balls 50 will again be conditioned to latch the latch rod 56 upon energization of the coil 72 of the relay.

To compensate for dimensional variations in the manufacture of different parts of the latch attachment 10 and the relay 12, the latch rod 56 is adjustable with respect to the formed retaining nut 62.

It will be seen that the frusto-conical inner cam surface 52 of the core 22 and the conical frustum portions 68 and 69 of the latch rod 56 cooperate with the latching balls 50 in the latch operating member 44 to provide an eflicient wear-free latching mechanism. When the movable contact carrier assembly 64 of the relay 12 and the latch rod 56 are in the unlatched position, as shown in FIG. 5, and the latch operating member 44 is in latching position, as shown in FIG. 2, and the relay 12 is energized to move the latch rod toward latched position, the inclined surfaces of portion 68 of the latch rod 56 and the surface 52 of the core 22 are divergent to prevent sticking of the latching balls 50 and excess wear of the parts, and the latch mechanism operates with very little friction and thus requires a relatively small amount of force to be moved by the electromagnet of the relay 12. Also, when the relay 12 is deenergized and the latch rod 56 is released, the divergent surfaces assure that the latch rod 56 moves to its fully released position, thus preventing excessive arcing between the contacts of the relay 12.

Various modifications may be made in the structure disclosed without departing from the spirit and scope of the invention.

What is claimed is:

1. A manually and electromagnetically operable latching device comprising a housing, an electrical coil in said housing, a magnetic core in said housing adapted to be magnetized upon energization of said coil, an armature in said housing normally spaced from said core and adapted to be attracted toward said core upon energization of said coil, a latch operating member extending outwardly of said housing and secured to said armature for movement as a unit therewith, a spring in said housing biasing said latch operating member inwardly of said housing, a plurality of latching balls carried by said latch operating member and retained therein by said core, a latch rod reciprocally mounted in said latch operating member and retainable by said latching balls in a latched position, and means for pulling said latch operating member outwardly of said housing against the biasing force of said spring, said latching balls being movable by said latch operating member out of latching relationship with said latch rod selectively by the pulling of said latch operating member outwardly of said housing and by energization of said coil.

2. A manually and electromagnetically operable latching device comprising a housing, an electrical coil in said housing, a generally cylindrical hollow magnetic core in said housing disposed centrally of said coil and adapted to be magnetized upon energization of said coil, said core: having a tapered inner cam surface, a generally cylindrical hollow armature in said housing disposed centrally of said coil and normally spaced from said core and adapted to be attracted toward said core upon energization of said coil, a generally cylindrical hollow latch operating member extending outwardly of said housing and secured to said armature for reciprocal movement axially thereof as a unit therewith, a spring in said housing biasing said latch operating member inwardly of said housing, a plurality of latching balls engageable with said tapered inner cam surface of said core and carried by said latch operating member for reciprocal movement therewith axially thereof and radial movement relatively thereto, a latch rod reciprocally mounted in said latch operating member and biased in the same direction said latch operating member is biased, said latch rod having a pair of tapered surfaces respectively generally defining a pair of conical frustums tapering outwardly toward each other, one of said conical frusturns positively moving said latching balls radially outwardly of said latch operating member and in a radially expanding direction along said tapered inner cam surface of said core when said latch rod is moved toward a latched position and the other of said conical frustums providing means for said latching balls respectively to exert forces on said latch rod partially axially thereof to positively latch said latch rod when said latch rod is in said latched position, and means for pulling said latch operating member outwardly of said housing against the biasing force of said spring, said latching balls being movable by said latch operating member out of latching relationship with said other conical frustum selectively by the pulling of said latch operating member outwardly of said housing and by energization of said coil.

3. A latching device as claimed in claim 1, wherein said magnetic core is provided with a tapered inner cam surface converging toward said armature and said latching balls are retained in said latch operating member by engagement with said cam surface.

4. A latching device as claimed in claim 1, wherein said latch rod is provided with a pair of reduced diameter portions spaced apart from each other axially of said latch rod and with a pair of base-to-base conical frustum portions joining said reduced portions,- one of said conical frustum portions positively moving said latching balls radially outwardly of said latch operating member when said latch rod is moved toward said latched position and the other of said conical frustum portions providing means for said latching balls to positively latch said latch rod when said latch rod is in said latched position.

5. A latching device as claimed in claim 1, wherein said latch operating member is provided with a plurality of radially extending circumferentially spaced apertures for respectively receiving said latching balls.

6. The combination including a latching device as claimed in claim 1 and a reciprocal actuating member movable as a unit with said latch rod to an operated position in which it is latchable by said latch rod, said actuating member being threadedly connected to an end portion of said latch rod to permit the position of said actuating member to be adjusted relatively to and axially of said latch rod.

7. The combination comprising an electromagnetic relay having a movable contact carrier assembly, and a manually and electromagnetically operable latching device, said latching device including a housing secured to said relay, an electrical coil in said housing, a magnetic core in said housing magnetizable upon energization of said coil, an armature in said housing normally spaced from said core and attractable toward said core upon energization of said coil, a latch operating member normally extending a predetermined distance outwardly of said housing on the opposite side thereof from said relay and secured to said armature for movement as a unit therewith, a spring in said housing biasing said latch operating member inwardly of said housing, a plurality of latching balls carried by said latch operating member and retained therein by said core, a latch rod reciprocally mounted in said latch operating member and retainable by said latching balls in a latched position, threaded means in said movable contact carrier assembly of said relay threadedly receiving one end portion of said latch rod, means on the other end portion of said latch rod for adjusting said latch rod relatively to said threaded means, and means for pulling said latch operating member farther outwardly of said housing against the biasing force of said spring, said latching balls being movable by said latch operating member out of latching relationship with said latch rod selectively by the pulling of said latch operating member farther outwardly of said housing and by the energization of said coil.

8. The combination comprising an electromagnetic relay having a cover removably secured thereto by a pair of spring clamps, and a manually and electromagnetically operable latching device having a housing removably securable to said relay by said pair of spring clamps after removal of said cover, said cover having a counterpart formed integrally with said housing, and said latching device including an electrical coil in said housing, a magnetic core in said housing magnetizable upon energization of said coil, an armature in said housing normally spaced from said core and attractable toward said core upon energization of said coil, a latch operating member normally extending a predetermined distance outwardly of said housing and secured to said armature for movement as a unit therewith, a spring in said housing biasing said latch operating member inwardly of said housing, a plurality of latching balls carried by said latch operating member and retained therein by said core, a latch rod reciprocally mounted in said latch operating member and retainable by said latching balls in a latched position, and means for pulling said latch operating member farther outwardly of said housing against the biasing force of said spring, said latching balls being movable by said latch operating member out of latching relationship with said latch rod selectively by the pulling of said latch operating member farther outwardly of said housing and by the energization of said coil.

References Cited by the Examiner UNITED STATES PATENTS 2,386,162 10/45 Hetherington 200-77 2,632,821 3/53 Wright et a1. 317l87 2,924,685 2/60 Burch 200l04 3,101,434 8/63 Kitscha 317-487 BERNARD A. GILHEANY, Primary Examiner.

ROBERT K. SCHAEFER, Examiner. 

1. A MANUALLY AND ELECTROMAGNETICALLY OPERABLE LATCHING DEVICE COMPRISING A HOUSING, AN ELECTRICAL COIL IN SAID HOUSING, A MAGNETIC CORE IN SAID HOUSING ADAPTED TO BE MAGNETIZED UPON ENERGIZATION OF SAID COIL, AN ARMATURE IN SAID HOUSING NORMALLY SPACED FROM SAID CORE AND ADAPTED TO BE ATTRACTED TOWARD SAID CORE UPON ENERGIZATION OF SAID COIL, A LATCH OPERATING MEMBER EXTENDING OUTWARDLY OF SAID HOUSING AND SECURED TO SAID ARMATURE FOR MOVEMENT AS A UNIT THEREWITH, A SPRING IN SAID HOUSING BIASING SAID LATCH OPERATING MEMBER INWARDLY OF SAID HOUSING, A PLURALITY OF LATCHING BALLS CARRIED BY SAID LATCH OPERATING MEMBER AND RETAINED THEREIN BY SAID CORE, A LATCH ROD RECIPROCALLY MOUNTED IN SAID LATCH OPERATING MEMBER AND RETAINABLE BY SAID LATCHING BALLS IN A LATCHED POSITION, AND MEANS FOR PULLING SAID LATCH OPERATING MEMBER OUTWARDLY OF SAID HOUSING AGAINST THE BIASING FORCE OF SAID SPRING, SAID LATCHING BALLS BEING MOVABLE BY SAID LATCH OPERATING MEMBER OUT OF LATCHING RELATIONSHIP WITH SAID LATCH ROD SELECTIVELY BY THE PULLING OF SAID LATCH OPERATING MEMBER OUTWARDLY OF SAID HOUSING AND BY ENERGIZATION OF SAID COIL. 